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Random disconnects

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Frequent Visitor

Random disconnects

We upgraded to 600 MBPS service recently from 150 MBPS and it may or may not be related but I have been getting random disconnects.  It happened again this morning 3 times, and the 3rd time it stayed down for hours.  Rebooted modem, router, etc multiple times, checked all connections even though nothing has changed. 

 

I set up a tech appt.   For reference we have a CM600 modem which is a docsis 3.0 modem which I dont think fully supports our new service speed but it should still provide the same solid service as we had before.  When it went down the last time I checked and we had 1 downstream channel locked and that was it.  No upstream.  I took a shower, came back and the modem is connected again, except now,  I only have 1 of 4 upstream channels locked, and my power levels look too high.   All downsteam channels are locked.

 

 

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 405000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enable BPI+
IP Provisioning Mode Honor MDD IPv6 only
 
<tabindex=-1>Downstream Bonded Channels</tabindex=-1>
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 8 405000000 Hz -3.5 dBmV 37.5 dB 0 0
2 Locked QAM256 9 411000000 Hz -3.5 dBmV 37.4 dB 0 0
3 Locked QAM256 10 417000000 Hz -3.5 dBmV 37.5 dB 0 0
4 Locked QAM256 11 423000000 Hz -3.3 dBmV 38.0 dB 0 0
5 Locked QAM256 12 429000000 Hz -3.4 dBmV 38.0 dB 0 0
6 Locked QAM256 13 435000000 Hz -3.3 dBmV 38.1 dB 0 0
7 Locked QAM256 14 441000000 Hz -3.4 dBmV 38.1 dB 0 0
8 Locked QAM256 15 447000000 Hz -3.5 dBmV 38.2 dB 0 0
9 Locked QAM256 16 453000000 Hz -3.6 dBmV 38.2 dB 0 0
10 Locked QAM256 17 459000000 Hz -3.8 dBmV 38.1 dB 0 0
11 Locked QAM256 18 465000000 Hz -4.0 dBmV 38.1 dB 0 0
12 Locked QAM256 19 471000000 Hz -4.1 dBmV 38.4 dB 0 0
13 Locked QAM256 20 477000000 Hz -4.2 dBmV 38.2 dB 0 0
14 Locked QAM256 21 483000000 Hz -4.3 dBmV 38.1 dB 0 0
15 Locked QAM256 22 489000000 Hz -4.4 dBmV 38.0 dB 0 0
16 Locked QAM256 23 495000000 Hz -4.4 dBmV 37.7 dB 0 0
17 Locked QAM256 24 501000000 Hz -4.9 dBmV 37.9 dB 0 0
18 Locked QAM256 25 507000000 Hz -4.8 dBmV 37.9 dB 0 0
19 Locked QAM256 26 513000000 Hz -4.7 dBmV 37.9 dB 0 0
20 Locked QAM256 27 519000000 Hz -4.9 dBmV 38.0 dB 0 0
21 Locked QAM256 28 525000000 Hz -4.8 dBmV 38.2 dB 0 0
22 Locked QAM256 29 531000000 Hz -4.5 dBmV 38.2 dB 0 0
23 Locked QAM256 30 537000000 Hz -4.3 dBmV 38.2 dB 0 0
24 Locked QAM256 31 543000000 Hz -4.0 dBmV 38.6 dB 0 0
 
<tabindex=-1>Upstream Bonded Channels</tabindex=-1>
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Locked ATDMA 3 5120 Ksym/sec 30300000 Hz 57.0 dBmV
2 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
3 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
4 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
5 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
6 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
7 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
8 Not Locked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
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Expert

Re: Random disconnects

That modem is rated by them for up to 959 Mbps speeds;

 

https://www.xfinity.com/support/devices#details

 

The upstream power is way too high / out of spec ! That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, and latency problems.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed, and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.



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